1. Structure of an atom:-
The basic structure of an atom includes a tiny, relatively massive nucleus, containing at least one proton and usually one or more neutrons.Outside of the nucleus are energy levels (also called shells), which contain one or more electrons.
Properties of an atom:-
The neutrons have the greatest mass and have no charge. The protons have slightly less mass than the neutrons and are positively charged. The electrons have almost no mass and are negatively charged. The chemical properties of the atom are determined by the number of protons, in fact, by number and arrangement of electrons.
2. Elements and their chemical symbols :-
1) Sodium - Na
2) Carbon - C
3) Magnesium - Mg
4) Aluminium - Al
5) Silicon - Si
6) Chlorine - Cl
7) Potassium - K
8) Calcium - Ca
9) Copper - Cu
10) Iron - Fe
3. ionic bond
Covalent bond
Metallic bond
4. pH scale used to specify the acidity or basicity of an aqueous solution. Acidic solutions are measured to have lower pH values than basic or alkaline solutions
5. There are four natural states of matter: Solids, liquids, gases and plasma.
6. Law of conservation of mass :
The 'law of conservation of mass' says that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. The mass of the products in a chemical reaction must equal the mass of the reactants.
Law of conservation of energy :-
According to the law of conservation of energy, energy can only be transformed from one form to another. It can neither be created nor destroyed. The total energy before and after the transformation always remains constant.
Explanation:
i understand the eclipse is often used to describe solar eclipse and when the moons shadow crosses Earth surface or it's when the moon moves into Earths shadow
Answer:
Molarity of HCl = 1.6M
Explanation:
The chemical reaction equation is;
HCl(aq) + NaOH(aq) —> NaCl(aq) + H2O(l)
Now, molarity = number of moles/volume
Thus, for NaOH, we have;
Number of moles = molarity × volume = 2M × (20/1000) L
Number of moles = 0.04 moles
Using the coefficients in the chemical equation above, we can find the corresponding number of moles for HCl.
Number of moles of HCl = 0.04 moles NaOH × (1 mole of HCl/1 mole of HCl) = 0.04 moles of HCl
Thus;
Molarity of HCl = 0.04/(25/1000)
Molarity of HCl = 1.6M
Answer:49.3
Explanation:4.1j/g c * 25g * (t2-45c)=455j
T2-45c = 455j/4.1j/g c * 25g
455/104.6
45+4.3= 49.3 celsius
Answer:
A star is made up of burning gases, while a comet is made up of ice, gases, rocks, and dust.
Explanation:
